Field of the Invention
Embodiments of the present invention relate generally to loudspeaker systems and, more specifically, to a manifold for multiple compression drivers with a single point source exit.
Description of the Related Art
Multiple compression drivers are commonly used to drive acoustic horns in loudspeakers that are designed to project sound for relatively long distances. For example, a loudspeaker in a public address system that is capable of projecting sound for hundreds of feet would typically include numerous compression drivers. However, when two compression drivers emit sound waves, the sound waves may generate acoustical reflections and interference. Such reflections and interference can lead to comb filtering (i.e., reinforcement of some sound waves and cancellation of other sound waves) and/or acoustic interference patterns that compromise the fidelity and intelligibility of the overall sound for the audience.
In an effort to achieve high sound pressure levels and, consequently, audio volumes while reducing comb filtering and acoustic interference patterns, various techniques for arranging multiple compression drivers have been employed. In such techniques, multiple compression drivers are usually mounted in a manifold that delivers sound to the throat end of the acoustic horn of the loudspeaker. In one such design, four compression drivers can be arranged within a relatively small manifold area. Two of the compression drivers form a skewed (i.e., “Y”) configuration, and the other two compression drivers are directly opposed to each other. With this overall configuration, the manifold routes the sound waves from the skewed drivers at angles of approximately forty-five degrees, reflects the sound waves from the opposed drivers at approximately ninety degrees, and then combines the four resulting sound waves to create an aggregated sound.
One drawback of this particular approach is that acoustic reflections and interference still persist within the manifold that can degrade the overall quality of the sound emanating from the manifold. In particular, the interactions of the four sound waves within the manifold can produce artifacts, such as crossmodes, that remain present when the four waveforms are combined. Those crossmodes and other similar artifacts degrade the quality of the sound ultimately produced via the manifold, which hinders the ability to produce high fidelity sound. In general, conventional approaches to combining multiple compression drivers suffer similar sound degradation that is attributable to interference and/or reflections within the manifold.
As the foregoing illustrates, more effective techniques for generating high fidelity sound through loudspeakers would be useful.